CWE

Wrap-around Error

ID: 128		Date: (C)2012-05-14   (M)2022-10-10
Type: weakness		Status: INCOMPLETE
Abstraction Type: Base

Description

Wrap around errors occur whenever a value is incremented past the maximum value for its type and therefore "wraps around" to a very small, negative, or undefined value.

Likelihood of Exploit: Medium

Applicable Platforms
Language: Often
Language: C
Language: Often
Language: C++

Time Of Introduction

• Implementation

Related Attack Patterns

• CAPEC-92

Common Consequences

Scope	Technical Impact	Notes
Availability	DoS: crash / exit / restart DoS: resource consumption (CPU) DoS: resource consumption (memory) DoS: instability	This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.
Integrity	Modify memory	If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality Availability Access_Control	Execute unauthorized code or commands Bypass protection mechanism	This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.

Detection Methods
None

Potential Mitigations

Phase	Strategy	Description	Effectiveness	Notes
		Requirements specification: The choice could be made to use a language that is not susceptible to these issues.
Architecture and Design		Provide clear upper and lower bounds on the scale of any protocols designed.
Implementation		Place sanity checks on all incremented variables to ensure that they remain within reasonable bounds.

Relationships
The relationship between overflow and wrap-around needs to be examined more closely, since several entries (including CWE-190) are closely related.

Related CWE	Type	View	Chain
CWE-128 ChildOf CWE-885	Category	CWE-888

Demonstrative Examples   (Details)

1. The following image processing code allocates a table for images. (Demonstrative Example Id DX-33)

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

Taxynomy	Id	Name	Fit
CLASP		Wrap-around error
CERT C Secure Coding	MEM07-C	Ensure that the arguments to calloc(), when multiplied, can be represented as a size_t
CERT C++ Secure Coding	MEM07-CPP	Ensure that the arguments to calloc(), when multiplied, can be represented as a size_t

References:

1. Michael Howard David LeBlanc John Viega .24 Deadly Sins of Software Security. McGraw-Hill. Section:'"Sin 5: Buffer Overruns." Page 89'. Published on 2010.
2. Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 6, "Signed Integer Boundaries", Page 220.'. Published on 2006.